The Development of the Investigative Function

• Thief Catcher: These people were hired by individuals to find stolen property.

The Realities of an Investigation

• Kansas City Response Time Study: The result of this study showed that people take longer to report crimes than it takes for an officer to arrive at the scene.

• Discovery Crime: Officers respond to crimes well after they were committed

• Involvement Crimes: Officers arrive while the crime is taking place.

• Clearance Rate: This refers to the rate at which a suspect is identified and caught.

The Preliminary Investigation

• Preliminary Investigation: This is the investigation that takes place when an officer arrives at the scene. it includes determining whether the offender is at the scene or area, if the victim needs help, and making sure everyone in the general area is safe.

• Contaminants: This refers to anything that may alter the crime scene.

• Reconstruction: Officers will try to determine exactly what happened at the crime scene and to determine what and how they did what they did and contaminants can alter that.

• Solvability Factors: These are factors that can affect the probability of success in solving the case.

The Follow Up Investigation

Types of Crime Scenes

• Crime Scene: Area where the majority of the evidence of a crime is.

• Primary Crime Scene: This is where the crime originally took place

• Secondary Crime Scene: This refers to any other place the crime took place (the transport car, where the body is buried, etc.)

Making the Case: Linking the Offender to a Crime Scene

• Locard Exchange Principle: This is the belief that an offender will take something with them from the crime scene and leave something as well.

• Chain of Evidence or Chain of Custody: This is the careful and detailed tracking of all physical evidence from a case.

• Records should include:

  • When and to whom the evidence was given too

  • Why the evidence was given

  • When and who returned the evidence

  • Conditions and location of evidence leading to the trial

• Types of Evidence

  • Fingerprints: No two people have the same fingerprint hence this can be used to identify an offender. We use AFIS to help find a match.

  • Blood: DNA profiling uses genetic material to identify individuals no one but identical twins have the same DNA.

  • Saliva: National DNA Index System has about 600,000 offenders and it can be shared between states.

  • Semen Skin: Federal law let us take blood samples from convicted felons.

  • Weapon: We can identify the weapons used and find the manufacturer which could potentially lead us to a suspect.

Establishing a Physical Link

• Associative evidence: Lab work that can be used to link the crime scene, victim, and offender

• Criminalistics: It is used to reconstruct what happened and it can be used to find links between people, places, and things.

Behavioral Evidence--Signature v. Modus Operandi

• Physical evidence: An object or item that can be linked to a crime

• Nonverbal cues: This refers to the way a suspect talks

• Kinesics: The body language of a suspect

• Cultural Cues: These are things based on the culture of a person. Nonverbal cues can be different based on a person’s religion. For example, some cultures believe no eye contact means defiance to authority but officers may believe it’s a sign of guilt.

• Criminal Profiling: Using the behavior present at a crime scene to determine what type of person committed the crime.

• Modus Operandi: This refers to “how” the crime was committed.

• Signature: This refers to “what” the offender does. This can help link multiple crimes and determine whether a series of crimes have a common offender.

• Organized Typology: This type of offender will meticulously plan their crime and will leave as little evidence as possible

• Disorganized Typology: This type of offender will be chaotic and will not plan their attack. They will usually leave a lot of evidence behind.

• Psychopath: This type of person charms their victim and does not have any empathy and it often results in them feeling sadistic sexual pleasure.

• Schizoid Personality: These types of people avoid social interactions and have a lower range of emotional expressions.

Information, Clearance Rates, and Investigation

• Circle of Investigation: The pool of possible suspects

• Violent Criminal Apprehension Program (VICAP): These logs crimes and their details to help law enforcement connect crimes.

• Integrated Ballistic Information System (IBIS): This is a firearm identification program

• Integrated Automated Fingerprint Identification System (IAFIS): This helps match fingerprints to other crimes or people and it works 24/7 all year. Usually, officers will get results in about two hours.

• Combined DNA Index System (CODIS): This compares DNA on a national level between federal, local, and state offenders.

Investigating Terror: Models of Counterterrorism

• Field Intelligence Groups (FIGs): These agents identify gaps in intelligence, analyze them, and disseminate findings to local law enforcement.

• Key factors in a successful terrorism investigation:

  • Task force concept

  • Recognition of terrorism as a specialty

  • Focusing on people committing a crime

  • Carefully gathering evidence